问题
选择题
下列运算正确的是（ ）
A．a2•a3=a6
B．（a4）3=a12
C．（﹣2a）3=﹣6a3
D．a（a﹣1）=a2﹣1
答案
B．
题目分析：A．a2•a3=a5，本选项错误；
B．（a4）3=a12，本选项正确；
C．（﹣2a）3=﹣8a3，本选项错误；
D．a（a﹣1）=a2﹣a，本选项错误．
故选B．
搜题请搜索小程序“爱下问搜题”
下列运算正确的是（ ）
A．a2•a3=a6
B．（a4）3=a12
C．（﹣2a）3=﹣6a3
D．a（a﹣1）=a2﹣1
B．
题目分析：A．a2•a3=a5，本选项错误；
B．（a4）3=a12，本选项正确；
C．（﹣2a）3=﹣8a3，本选项错误；
D．a（a﹣1）=a2﹣a，本选项错误．
故选B．
| 选用方框中合适的句子，补全对话。 | |
| A: MeiMei, you look worried. What is the matter with you? B: 1_____ Then I am too tired to do well in the exam. A: That is too bad. 2_____ B: Yes. They say they don't know what to do. 3_____ A: What about your teacher? B: He says I should study harder, then I will feel better. But I have studied harder now. A: 4_____ B: Go out for a walk before the exam? Is that OK? A: 5_____ B: I will try. | |
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